Fuse



J. B. SEMPLE.

FUSE.

APPLICATION FILED MAY 20, 1920.

136,476.. Patented Feb. 22, 1921. 4

UNITED STATES PATENT OFFICE.

JOHN B. SEMPLE, OI SEW ICKLEY, PENNSYLVANIA.

rusn.

Specification of Letters Patent. Patented Feb, 22, 1921 Application filed May 20, 1920. Serial No. 382,933.

. gitudinal medial section the fuse member as it isapplied to a'shell; Fig. II is, a like view to larger scale of a portion of the structure shown in Fig. I.

The fuse is, as is customary, carried in a stock 1, adapted to be screwed into position in an opening formed in the wall of a shell..

It includes as its essential elements a percussion cap or primer 2, with means for fir- A in it, a detonator 3; and, in addition, a

third element, not essential though ordinarily present, a booster charge 4. The means for firing the primer include hammer and anvil members 5 and 6, one ordinarily secured permanently against movement within the stock, the other secure under all ordinary stresses, but with securing means, such as-shear-pin 7, rendered ineflective under-the extreme shock incident to the firing of the shell from a gun, leaving hammer and anvil members relatively movable, to the end that on impact (when the flying shell strikes) the primer will be fired. These featuresare old, and the exemplar presentation. which the drawing afior s will sufiice, It will be understood that the fuse to which 'my invention is applicable is one in which the primer is fired on impact, but as to the arrangement of and the arming of the firing meansthese are matters which may be varied-at will, as the one who practises my invention may prefer.

A pas'sageway'le'ads from primer to detonator. -In ordinary practice this is merely an open canal, through which the flash of the primer is, projected to impinge upon and fire the detonator 'withoutappreciable delay, and it is at this point that the peculiarity in structure resides, in which my present invention consists; I screen the dot-- on'ator behind a barrier, and I provide means, efi'eotive only after a delay, by which fect ignition of the detonator beyond. Such means constitute in effect a relay for the primer-a relay, ignited by the primer, which, continuing to burn during a relatively long interval oftime, 'will ultimately surmount the barrier, and-in one manner or another of those suggested, efi'ect ignition of the detonator.

The barrier which screens the detonator is in the drawings indicated at 8; it may be formed of celluloid, for example, and in that case, being ignited, it will burn away and expose and indeed impart ignition'to the detonator; it may be a thin septum of lead, or of another metal or an alloy of low melting point, and in that case it will under continued impact of a jet of flame melt away, exposing the detonator; or, again, the barrier, lying close upon the substance of the detonator, may be formed of copper or of other metal of good heat conductivity, to the end that the heat from the relay communicated through the barrier, even thou h it does not destroy the barrier, will still 1gnite the detonator beyond. The thickness of the barrier is the factor which, other things being equal, will determine'the du-.

ration of delay; if the barrier be thin, the

delay will be short; if thick, it will be long.-

The relay for the primer has this characteristic: it affords heat or flame, which be ing for a prolonged interval of time exerted upon the barrier covering the detonator,.

penetrates it. As I have said, in the usual fuse construction an open duct leads from primer to detonator. In the embodiment of the invention shown in the drawings a relay char e of suitable material, conveniently blac powder, is arranged between primer and detonator where ordinarily the open duct is found. This relay charge repowder. The chamber preferably is contracted at the end adjacent the detonator to a narrow orifice 13. Through the center of this body 9 and in line between primer and detonator and continuous with orifice 13 is I a duct which is filled with a body of loose or relatively uncompressed black powder. The compound body of powder 9, 10-does not extend all'the way to the barrier S which faces the detonator; there is an interval between, and preferably the normal flashway is there enlarged, afiording an overflow space 11, for the gases generated teristic is that it will detonate under heat or flame, penetrating barrier ..8 from relay charge 9.

The operation is easily understood: On impact of the shell the. primer 2 is fired. The flash of the primer," impinging on the body 10 of loose owder, ignites it. This body 10 is imme iately consumed; in its consumption cork 12 is driven into space 11,

a passageway to the detonator is opened, and

the body 9 of compressed owder is ignited.

'- The bod 9 burnsgradua l andjdurin'g a I 8 which faces detonator 3.

sufficient prolonged perio the burning of body 9 af brds a jetof flame which escaping through orifice 13 impinges u on thebarrier enetralion of the. barrierensues (either bodil penetration of the flame, in consequence o the burningor the melting of the barrier,.or penetration. of heat alone), after an interval predetermined in the selection of material for'and;

the proportioning of the barrier 8. Itistlfiis interval of dela which constitutes thefuse a delay-acting use. i g

I claim as my invention:

'19 In a delay-acting detonating fuse,' the combination of a primer, a detonator, a septum screening the detonator from imme-' diate ignition by the flame from the primer, and a gradually combustible relay receiving ignition from the primer and in course of burning delivering upon the septum acontinuing flame, substantially as described.

2. In a delay-acting fuse detonating u on by impact of theshell whichcar-ries it,.a det--- impact the combination of a primer fir onator, a barrier screen between detonator and primer, a gradually combustible relay between screen and primer, said relay" exposed to the flash of said primer and in course of burning delivering in turn a continuing flame upon said screen, substantially as described.

,3. In a dela -acting detonating fuse, the combination 0 a 'detonator; a barrier screen facing said detonator, and means for bringing to bear for a prolonged interval of time a flame upon said screen, such means including a chamber with restricted orifice, a body of compressed black powder within said chamber and 'having a central bore alined' with said orifice filled with loose black powder, and means for imparting ignition to the body of loose powder within said bore,

substantially as described.

' 4. A delay-acting detonating fuse including in combination a primer and a detonator, a barrier screen facing-the detonator, anda rela charge including a body of compressed b ack powder, .with a bore through it, and a body of lose black powder filling such bore, said bore exposed on one side to the flash of the primer and opening on the other side to the barrier-faced detonator, substantially as described.

5.] A delay-acting detonating fuse including in combination a detonator, a barrier screen facing said detonator, means for bringing to bear for a prolongedinterval of time a flame upon sai screen, such means including a chamber having a contracted orifice arranged opposite said barrier-faced detonator, combustible material within said chamber, and means for .imparting'combus tion to the body of material within said chamber, substantiall as described.

6. A delay-acting etonati'ng fuse including in com ination aprimer, a gradually combustible body affordin a flame of pro- ?i -i1Ol1ged duration arrange to receive the.

flash of "the primer, and a detonator screened-by a barrier gradually yielding to enetration of adetonato'r-igmting impulse inherent in flame and arranged to. receive throughout the eriod of burning the flame of the said combustible body, substantially as described.

I In testimony whereof I have hereunto set myhand; JOHN B. SEMPLE.

' Witnesses;

B'AYARD H. Cmusrr,

FRANCIS J TouAssoN. 

